package com.mbschenkel.client;

public class Hash {
	/**
	 * Fast implementation of RSA's MD5 hash generator in Java JDK Beta-2 or higher.
	 * <p>
	 * Originally written by Santeri Paavolainen, Helsinki Finland 1996.<br>
	 * (c) Santeri Paavolainen, Helsinki Finland 1996<br>
	 * Many changes Copyright (c) 2002 - 2008 Timothy W Macinta<br>
	 * <p>
	 * This library is free software; you can redistribute it and/or
	 * modify it under the terms of the GNU Library General Public
	 * License as published by the Free Software Foundation; either
	 * version 2.1 of the License, or (at your option) any later version.
	 * <p>
	 * This library is distributed in the hope that it will be useful,
	 * but WITHOUT ANY WARRANTY; without even the implied warranty of
	 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	 * Library General Public License for more details.
	 * <p>
	 * You should have received a copy of the GNU Library General Public
	 * License along with this library; if not, write to the Free
	 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	 * <p>
	 * See http://www.twmacinta.com/myjava/fast_md5.php for more information
	 * on this file and the related files.
	 * <p>
	 * This was originally a rather straight re-implementation of the
	 * reference implementation given in RFC1321 by RSA.  It passes the MD5
	 * test suite as defined in RFC1321.
	 * <p>
	 *
	 * @author Santeri Paavolainen <sjpaavol@cc.helsinki.fi>
	 * @author Timothy W Macinta (twm@alum.mit.edu) (optimizations and bug fixes)
	 */

	static class MD5State {
	  /**
	   * 128-bit state 
	   */
	  int	state[];
	  
	  /**
	   * 64-bit character count
	   */
	  long count;
	  
	  /**
	   * 64-byte buffer (512 bits) for storing to-be-hashed characters
	   */
	  byte	buffer[];

	  public MD5State() {
	    buffer = new byte[64];
	    count = 0;
	    state = new int[4];
	    
	    state[0] = 0x67452301;
	    state[1] = 0xefcdab89;
	    state[2] = 0x98badcfe;
	    state[3] = 0x10325476;
	  }

	  /** Create this State as a copy of another state */
	  public MD5State (MD5State from) {
	    this();
	    
	    int i;
	    
	    for (i = 0; i < buffer.length; i++)
	      this.buffer[i] = from.buffer[i];
	    
	    for (i = 0; i < state.length; i++)
	      this.state[i] = from.state[i];
	    
	    this.count = from.count;
	  }
	};
	
	public static class MD5 {
	    
	    /**
	     * MD5 state
	     **/
	    MD5State state;
	    
	    /**
	     * If Final() has been called, finals is set to the current finals
	     * state. Any Update() causes this to be set to null.
	     **/
	    MD5State finals;
	    
	    /** 
	     * Padding for Final()
	     **/
	    static byte padding[] = {
	        (byte) 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
	        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
	    };
	    
	    
	    /**
	     * Initialize MD5 internal state (object can be reused just by
	     * calling Init() after every Final()
	     **/
	    public synchronized void Init () {
	        state = new MD5State();
	        finals = null;
	    }
	    
	    /**
	     * Class constructor
	     **/
	    public MD5 () {
	        this.Init();
	    }
	    
	    /**
	     * Initialize class, and update hash with ob.toString()
	     *
	     * @param ob Object, ob.toString() is used to update hash
	     *           after initialization
	     **/
	    public MD5 (Object ob) {
	        this();
	        Update(ob.toString());
	    }
	    
	    private void Decode (byte buffer[], int shift, int[] out) {
	        /*len += shift;
	        for (int i = 0; shift < len; i++, shift += 4) {
	            out[i] = ((int) (buffer[shift] & 0xff)) |
	                (((int) (buffer[shift + 1] & 0xff)) << 8) |
	                (((int) (buffer[shift + 2] & 0xff)) << 16) |
	                (((int)  buffer[shift + 3]) << 24);
	        }*/
	        
	        // unrolled loop (original loop shown above)
	        
	        out[0] = ((int) (buffer[shift] & 0xff)) |
	            (((int) (buffer[shift + 1] & 0xff)) << 8) |
	            (((int) (buffer[shift + 2] & 0xff)) << 16) |
	            (((int)  buffer[shift + 3]) << 24);
	        out[1] = ((int) (buffer[shift + 4] & 0xff)) |
	            (((int) (buffer[shift + 5] & 0xff)) << 8) |
	            (((int) (buffer[shift + 6] & 0xff)) << 16) |
	            (((int)  buffer[shift + 7]) << 24);
	        out[2] = ((int) (buffer[shift + 8] & 0xff)) |
	            (((int) (buffer[shift + 9] & 0xff)) << 8) |
	            (((int) (buffer[shift + 10] & 0xff)) << 16) |
	            (((int)  buffer[shift + 11]) << 24);
	        out[3] = ((int) (buffer[shift + 12] & 0xff)) |
	            (((int) (buffer[shift + 13] & 0xff)) << 8) |
	            (((int) (buffer[shift + 14] & 0xff)) << 16) |
	            (((int)  buffer[shift + 15]) << 24);
	        out[4] = ((int) (buffer[shift + 16] & 0xff)) |
	            (((int) (buffer[shift + 17] & 0xff)) << 8) |
	            (((int) (buffer[shift + 18] & 0xff)) << 16) |
	            (((int)  buffer[shift + 19]) << 24);
	        out[5] = ((int) (buffer[shift + 20] & 0xff)) |
	            (((int) (buffer[shift + 21] & 0xff)) << 8) |
	            (((int) (buffer[shift + 22] & 0xff)) << 16) |
	            (((int)  buffer[shift + 23]) << 24);
	        out[6] = ((int) (buffer[shift + 24] & 0xff)) |
	            (((int) (buffer[shift + 25] & 0xff)) << 8) |
	            (((int) (buffer[shift + 26] & 0xff)) << 16) |
	            (((int)  buffer[shift + 27]) << 24);
	        out[7] = ((int) (buffer[shift + 28] & 0xff)) |
	            (((int) (buffer[shift + 29] & 0xff)) << 8) |
	            (((int) (buffer[shift + 30] & 0xff)) << 16) |
	            (((int)  buffer[shift + 31]) << 24);
	        out[8] = ((int) (buffer[shift + 32] & 0xff)) |
	            (((int) (buffer[shift + 33] & 0xff)) << 8) |
	            (((int) (buffer[shift + 34] & 0xff)) << 16) |
	            (((int)  buffer[shift + 35]) << 24);
	        out[9] = ((int) (buffer[shift + 36] & 0xff)) |
	            (((int) (buffer[shift + 37] & 0xff)) << 8) |
	            (((int) (buffer[shift + 38] & 0xff)) << 16) |
	            (((int)  buffer[shift + 39]) << 24);
	        out[10] = ((int) (buffer[shift + 40] & 0xff)) |
	            (((int) (buffer[shift + 41] & 0xff)) << 8) |
	            (((int) (buffer[shift + 42] & 0xff)) << 16) |
	            (((int)  buffer[shift + 43]) << 24);
	        out[11] = ((int) (buffer[shift + 44] & 0xff)) |
	            (((int) (buffer[shift + 45] & 0xff)) << 8) |
	            (((int) (buffer[shift + 46] & 0xff)) << 16) |
	            (((int)  buffer[shift + 47]) << 24);
	        out[12] = ((int) (buffer[shift + 48] & 0xff)) |
	            (((int) (buffer[shift + 49] & 0xff)) << 8) |
	            (((int) (buffer[shift + 50] & 0xff)) << 16) |
	            (((int)  buffer[shift + 51]) << 24);
	        out[13] = ((int) (buffer[shift + 52] & 0xff)) |
	            (((int) (buffer[shift + 53] & 0xff)) << 8) |
	            (((int) (buffer[shift + 54] & 0xff)) << 16) |
	            (((int)  buffer[shift + 55]) << 24);
	        out[14] = ((int) (buffer[shift + 56] & 0xff)) |
	            (((int) (buffer[shift + 57] & 0xff)) << 8) |
	            (((int) (buffer[shift + 58] & 0xff)) << 16) |
	            (((int)  buffer[shift + 59]) << 24);
	        out[15] = ((int) (buffer[shift + 60] & 0xff)) |
	            (((int) (buffer[shift + 61] & 0xff)) << 8) |
	            (((int) (buffer[shift + 62] & 0xff)) << 16) |
	            (((int)  buffer[shift + 63]) << 24);
	    }
	    
	    private void Transform (MD5State state, byte buffer[], int shift, int[] decode_buf) {
	        int
	            a = state.state[0],
	            b = state.state[1],
	            c = state.state[2],
	            d = state.state[3],
	            x[] = decode_buf;
	        
	        Decode(buffer, shift, decode_buf);
	        
	        /* Round 1 */
	        a += ((b & c) | (~b & d)) + x[ 0] + 0xd76aa478; /* 1 */
	        a = ((a << 7) | (a >>> 25)) + b;
	        d += ((a & b) | (~a & c)) + x[ 1] + 0xe8c7b756; /* 2 */
	        d = ((d << 12) | (d >>> 20)) + a;
	        c += ((d & a) | (~d & b)) + x[ 2] + 0x242070db; /* 3 */
	        c = ((c << 17) | (c >>> 15)) + d;
	        b += ((c & d) | (~c & a)) + x[ 3] + 0xc1bdceee; /* 4 */
	        b = ((b << 22) | (b >>> 10)) + c;
	        
	        a += ((b & c) | (~b & d)) + x[ 4] + 0xf57c0faf; /* 5 */
	        a = ((a << 7) | (a >>> 25)) + b;
	        d += ((a & b) | (~a & c)) + x[ 5] + 0x4787c62a; /* 6 */
	        d = ((d << 12) | (d >>> 20)) + a;
	        c += ((d & a) | (~d & b)) + x[ 6] + 0xa8304613; /* 7 */
	        c = ((c << 17) | (c >>> 15)) + d;
	        b += ((c & d) | (~c & a)) + x[ 7] + 0xfd469501; /* 8 */
	        b = ((b << 22) | (b >>> 10)) + c;
	        
	        a += ((b & c) | (~b & d)) + x[ 8] + 0x698098d8; /* 9 */
	        a = ((a << 7) | (a >>> 25)) + b;
	        d += ((a & b) | (~a & c)) + x[ 9] + 0x8b44f7af; /* 10 */
	        d = ((d << 12) | (d >>> 20)) + a;
	        c += ((d & a) | (~d & b)) + x[10] + 0xffff5bb1; /* 11 */
	        c = ((c << 17) | (c >>> 15)) + d;
	        b += ((c & d) | (~c & a)) + x[11] + 0x895cd7be; /* 12 */
	        b = ((b << 22) | (b >>> 10)) + c;
	        
	        a += ((b & c) | (~b & d)) + x[12] + 0x6b901122; /* 13 */
	        a = ((a << 7) | (a >>> 25)) + b;
	        d += ((a & b) | (~a & c)) + x[13] + 0xfd987193; /* 14 */
	        d = ((d << 12) | (d >>> 20)) + a;
	        c += ((d & a) | (~d & b)) + x[14] + 0xa679438e; /* 15 */
	        c = ((c << 17) | (c >>> 15)) + d;
	        b += ((c & d) | (~c & a)) + x[15] + 0x49b40821; /* 16 */
	        b = ((b << 22) | (b >>> 10)) + c;
	        
	        
	        /* Round 2 */
	        a += ((b & d) | (c & ~d)) + x[ 1] + 0xf61e2562; /* 17 */
	        a = ((a << 5) | (a >>> 27)) + b;
	        d += ((a & c) | (b & ~c)) + x[ 6] + 0xc040b340; /* 18 */
	        d = ((d << 9) | (d >>> 23)) + a;
	        c += ((d & b) | (a & ~b)) + x[11] + 0x265e5a51; /* 19 */
	        c = ((c << 14) | (c >>> 18)) + d;
	        b += ((c & a) | (d & ~a)) + x[ 0] + 0xe9b6c7aa; /* 20 */
	        b = ((b << 20) | (b >>> 12)) + c;
	        
	        a += ((b & d) | (c & ~d)) + x[ 5] + 0xd62f105d; /* 21 */
	        a = ((a << 5) | (a >>> 27)) + b;
	        d += ((a & c) | (b & ~c)) + x[10] + 0x02441453; /* 22 */
	        d = ((d << 9) | (d >>> 23)) + a;
	        c += ((d & b) | (a & ~b)) + x[15] + 0xd8a1e681; /* 23 */
	        c = ((c << 14) | (c >>> 18)) + d;
	        b += ((c & a) | (d & ~a)) + x[ 4] + 0xe7d3fbc8; /* 24 */
	        b = ((b << 20) | (b >>> 12)) + c;
	        
	        a += ((b & d) | (c & ~d)) + x[ 9] + 0x21e1cde6; /* 25 */
	        a = ((a << 5) | (a >>> 27)) + b;
	        d += ((a & c) | (b & ~c)) + x[14] + 0xc33707d6; /* 26 */
	        d = ((d << 9) | (d >>> 23)) + a;
	        c += ((d & b) | (a & ~b)) + x[ 3] + 0xf4d50d87; /* 27 */
	        c = ((c << 14) | (c >>> 18)) + d;
	        b += ((c & a) | (d & ~a)) + x[ 8] + 0x455a14ed; /* 28 */
	        b = ((b << 20) | (b >>> 12)) + c;
	        
	        a += ((b & d) | (c & ~d)) + x[13] + 0xa9e3e905; /* 29 */
	        a = ((a << 5) | (a >>> 27)) + b;
	        d += ((a & c) | (b & ~c)) + x[ 2] + 0xfcefa3f8; /* 30 */
	        d = ((d << 9) | (d >>> 23)) + a;
	        c += ((d & b) | (a & ~b)) + x[ 7] + 0x676f02d9; /* 31 */
	        c = ((c << 14) | (c >>> 18)) + d;
	        b += ((c & a) | (d & ~a)) + x[12] + 0x8d2a4c8a; /* 32 */
	        b = ((b << 20) | (b >>> 12)) + c;
	        
	        
	        /* Round 3 */
	        a += (b ^ c ^ d) + x[ 5] + 0xfffa3942;      /* 33 */
	        a = ((a << 4) | (a >>> 28)) + b;
	        d += (a ^ b ^ c) + x[ 8] + 0x8771f681;      /* 34 */
	        d = ((d << 11) | (d >>> 21)) + a;
	        c += (d ^ a ^ b) + x[11] + 0x6d9d6122;      /* 35 */
	        c = ((c << 16) | (c >>> 16)) + d;
	        b += (c ^ d ^ a) + x[14] + 0xfde5380c;      /* 36 */
	        b = ((b << 23) | (b >>> 9)) + c;
	        
	        a += (b ^ c ^ d) + x[ 1] + 0xa4beea44;      /* 37 */
	        a = ((a << 4) | (a >>> 28)) + b;
	        d += (a ^ b ^ c) + x[ 4] + 0x4bdecfa9;      /* 38 */
	        d = ((d << 11) | (d >>> 21)) + a;
	        c += (d ^ a ^ b) + x[ 7] + 0xf6bb4b60;      /* 39 */
	        c = ((c << 16) | (c >>> 16)) + d;
	        b += (c ^ d ^ a) + x[10] + 0xbebfbc70;      /* 40 */
	        b = ((b << 23) | (b >>> 9)) + c;
	        
	        a += (b ^ c ^ d) + x[13] + 0x289b7ec6;      /* 41 */
	        a = ((a << 4) | (a >>> 28)) + b;
	        d += (a ^ b ^ c) + x[ 0] + 0xeaa127fa;      /* 42 */
	        d = ((d << 11) | (d >>> 21)) + a;
	        c += (d ^ a ^ b) + x[ 3] + 0xd4ef3085;      /* 43 */
	        c = ((c << 16) | (c >>> 16)) + d;
	        b += (c ^ d ^ a) + x[ 6] + 0x04881d05;      /* 44 */
	        b = ((b << 23) | (b >>> 9)) + c;
	        
	        a += (b ^ c ^ d) + x[ 9] + 0xd9d4d039;      /* 33 */
	        a = ((a << 4) | (a >>> 28)) + b;
	        d += (a ^ b ^ c) + x[12] + 0xe6db99e5;      /* 34 */
	        d = ((d << 11) | (d >>> 21)) + a;
	        c += (d ^ a ^ b) + x[15] + 0x1fa27cf8;      /* 35 */
	        c = ((c << 16) | (c >>> 16)) + d;
	        b += (c ^ d ^ a) + x[ 2] + 0xc4ac5665;      /* 36 */
	        b = ((b << 23) | (b >>> 9)) + c;
	        
	        
	        /* Round 4 */
	        a += (c ^ (b | ~d)) + x[ 0] + 0xf4292244; /* 49 */
	        a = ((a << 6) | (a >>> 26)) + b;
	        d += (b ^ (a | ~c)) + x[ 7] + 0x432aff97; /* 50 */
	        d = ((d << 10) | (d >>> 22)) + a;
	        c += (a ^ (d | ~b)) + x[14] + 0xab9423a7; /* 51 */
	        c = ((c << 15) | (c >>> 17)) + d;
	        b += (d ^ (c | ~a)) + x[ 5] + 0xfc93a039; /* 52 */
	        b = ((b << 21) | (b >>> 11)) + c;
	        
	        a += (c ^ (b | ~d)) + x[12] + 0x655b59c3; /* 53 */
	        a = ((a << 6) | (a >>> 26)) + b;
	        d += (b ^ (a | ~c)) + x[ 3] + 0x8f0ccc92; /* 54 */
	        d = ((d << 10) | (d >>> 22)) + a;
	        c += (a ^ (d | ~b)) + x[10] + 0xffeff47d; /* 55 */
	        c = ((c << 15) | (c >>> 17)) + d;
	        b += (d ^ (c | ~a)) + x[ 1] + 0x85845dd1; /* 56 */
	        b = ((b << 21) | (b >>> 11)) + c;
	        
	        a += (c ^ (b | ~d)) + x[ 8] + 0x6fa87e4f; /* 57 */
	        a = ((a << 6) | (a >>> 26)) + b;
	        d += (b ^ (a | ~c)) + x[15] + 0xfe2ce6e0; /* 58 */
	        d = ((d << 10) | (d >>> 22)) + a;
	        c += (a ^ (d | ~b)) + x[ 6] + 0xa3014314; /* 59 */
	        c = ((c << 15) | (c >>> 17)) + d;
	        b += (d ^ (c | ~a)) + x[13] + 0x4e0811a1; /* 60 */
	        b = ((b << 21) | (b >>> 11)) + c;
	        
	        a += (c ^ (b | ~d)) + x[ 4] + 0xf7537e82; /* 61 */
	        a = ((a << 6) | (a >>> 26)) + b;
	        d += (b ^ (a | ~c)) + x[11] + 0xbd3af235; /* 62 */
	        d = ((d << 10) | (d >>> 22)) + a;
	        c += (a ^ (d | ~b)) + x[ 2] + 0x2ad7d2bb; /* 63 */
	        c = ((c << 15) | (c >>> 17)) + d;
	        b += (d ^ (c | ~a)) + x[ 9] + 0xeb86d391; /* 64 */
	        b = ((b << 21) | (b >>> 11)) + c;
	        
	        state.state[0] += a;
	        state.state[1] += b;
	        state.state[2] += c;
	        state.state[3] += d;
	    }
	    
	    /**
	     * Updates hash with the bytebuffer given (using at maximum length bytes from
	     * that buffer)
	     *
	     * @param stat   Which state is updated
	     * @param buffer Array of bytes to be hashed
	     * @param offset Offset to buffer array
	     * @param length Use at maximum `length' bytes (absolute
	     *               maximum is buffer.length)
	     */
	    public void Update (MD5State stat, byte buffer[], int offset, int length) {
	        int index, partlen, i, start;
	        finals = null;
	        
	        /* Length can be told to be shorter, but not inter */
	        if ((length - offset)> buffer.length)
	            length = buffer.length - offset;
	        
	        /* compute number of bytes mod 64 */
	        
	        index = (int) (stat.count & 0x3f);
	        stat.count += length;
	        
	        partlen = 64 - index;
	        
	        if (length >= partlen) {
	            	            
                int[] decode_buf = new int[16];
                if (partlen == 64) {
                    partlen = 0;
                } else {
                    for (i = 0; i < partlen; i++)
                        stat.buffer[i + index] = buffer[i + offset];
                    Transform(stat, stat.buffer, 0, decode_buf);
                }
                for (i = partlen; (i + 63) < length; i+= 64) {
                    Transform(stat, buffer, i + offset, decode_buf);
                }
	            index = 0;
	        } else {
	            i = 0;
	        }
	        
	        /* buffer remaining input */
	        if (i < length) {
	            start = i;
	            for (; i < length; i++) {
	                stat.buffer[index + i - start] = buffer[i + offset];
	            }
	        }
	    }
	    
	    /* 
	     * Update()s for other datatypes than byte[] also. Update(byte[], int)
	     * is only the main driver.
	     */
	    
	    /**
	     * Plain update, updates this object
	     **/
	    public void Update (byte buffer[], int offset, int length) {
	        Update(this.state, buffer, offset, length);
	    }
	    
	    public void Update (byte buffer[], int length) {
	        Update(this.state, buffer, 0, length);
	    }
	    
	    /**
	     * Updates hash with given array of bytes
	     *
	     * @param buffer Array of bytes to use for updating the hash
	     **/
	    public void Update (byte buffer[]) {
	        Update(buffer, 0, buffer.length);
	    }
	    
	    /**
	     * Updates hash with a single byte
	     *
	     * @param b Single byte to update the hash
	     **/
	    public void Update (byte b) {
	        byte buffer[] = new byte[1];
	        buffer[0] = b;
	        
	        Update(buffer, 1);
	    }
	    
	    /**
	     * Update buffer with given string.  Note that because the version of
	     * the s.getBytes() method without parameters is used to convert the
	     * string to a byte array, the results of this method may be different
	     * on different platforms.  The s.getBytes() method converts the string
	     * into a byte array using the current platform's default character set
	     * and may therefore have different results on platforms with different
	     * default character sets.  If a version that works consistently
	     * across platforms with different default character sets is desired,
	     * use the overloaded version of the Update() method which takes a
	     * string and a character encoding.
	     *
	     * @param s String to be update to hash (is used as s.getBytes())
	     **/
	    public void Update (String s) {
	        //byte chars[] = s.getBytes();
	    	int l = s.length();
	    	byte chars[] = new byte[ l ];
	    	for( int i=0;i<l;i++) 
	    		chars[i] = (byte) s.charAt(i);
	        Update(chars, chars.length);
	    }
	    
	    /**
	     * Update buffer with a single integer (only & 0xff part is used,
	     * as a byte)
	     *
	     * @param i Integer value, which is then converted to byte as i & 0xff
	     **/
	    public void Update (int i) {
	        Update((byte) (i & 0xff));
	    }
	    
	    private byte[] Encode (int input[], int len) {
	        int i, j;
	        byte out[];
	        
	        out = new byte[len];
	        
	        for (i = j = 0; j  < len; i++, j += 4) {
	            out[j] = (byte) (input[i] & 0xff);
	            out[j + 1] = (byte) ((input[i] >>> 8) & 0xff);
	            out[j + 2] = (byte) ((input[i] >>> 16) & 0xff);
	            out[j + 3] = (byte) ((input[i] >>> 24) & 0xff);
	        }
	        
	        return out;
	    }
	    
	    /**
	     * Returns array of bytes (16 bytes) representing hash as of the
	     * current state of this object. Note: getting a hash does not
	     * invalidate the hash object, it only creates a copy of the real
	     * state which is finalized. 
	     *
	     * @return Array of 16 bytes, the hash of all updated bytes
	     **/
	    public synchronized byte[] Final () {
	        byte bits[];
	        int index, padlen;
	        MD5State fin;
	        
	        if (finals == null) {
	            fin = new MD5State(state);
	            
	            int[] count_ints = {(int) (fin.count << 3), (int) (fin.count >> 29)};
	            bits = Encode(count_ints, 8);
	            
	            index = (int) (fin.count & 0x3f);
	            padlen = (index < 56) ? (56 - index) : (120 - index);
	            
	            Update(fin, padding, 0, padlen);
	            Update(fin, bits, 0, 8);
	            
	            /* Update() sets finals to null */
	            finals = fin;
	        } 
	        
	        return Encode(finals.state, 16);
	    }
	    
	    private static final char[] HEX_CHARS = {'0', '1', '2', '3',
	                                             '4', '5', '6', '7',
	                                             '8', '9', 'a', 'b',
	                                             'c', 'd', 'e', 'f',};
	    
	    /**
	     * Turns array of bytes into string representing each byte as
	     * unsigned hex number.
	     * 
	     * @param hash Array of bytes to convert to hex-string
	     * @return Generated hex string
	     */
	    public static String asHex (byte hash[]) {
	        char buf[] = new char[hash.length * 2];
	        for (int i = 0, x = 0; i < hash.length; i++) {
	            buf[x++] = HEX_CHARS[(hash[i] >>> 4) & 0xf];
	            buf[x++] = HEX_CHARS[hash[i] & 0xf];
	        }
	        return new String(buf);
	    }
	    
	    /**
	     * Returns 32-character hex representation of this objects hash
	     *
	     * @return String of this object's hash
	     */
	    public String asHex () {
	        return asHex(this.Final());
	    }
	    
	    /**
	     * Calculates and returns the hash of the contents of the given file.
	     **
	    public static byte[] getHash (File f) throws IOException {
	        if (!f.exists()) throw new FileNotFoundException(f.toString());
	        InputStream close_me = null;
	        try {
	            long buf_size = f.length();
	            if (buf_size < 512) buf_size = 512;
	            if (buf_size > 65536) buf_size = 65536;
	            byte[] buf = new byte[(int) buf_size];
	            MD5InputStream in = new MD5InputStream(new FileInputStream(f));
	            close_me = in;
	            while (in.read(buf) != -1);
	            in.close();
	            return in.hash();
	        } catch (IOException e) {
	            if (close_me != null) try { close_me.close(); } catch (Exception e2) {}
	            throw e;
	        }
	    }
	    */
	    /**
	     * @return true iff the first 16 bytes of both hash1 and hash2 are
	     *         equal;  both hash1 and hash2 are null; or either hash
	     *         array is less than 16 bytes in length and their lengths and
	     *         all of their bytes are equal.
	     **/
	    public static boolean hashesEqual (byte[] hash1, byte[] hash2) {
	        if (hash1 == null) return hash2 == null;
	        if (hash2 == null) return false;
	        int targ = 16;
	        if (hash1.length < 16) {
	            if (hash2.length != hash1.length) return false;
	            targ = hash1.length;
	        } else if (hash2.length < 16) {
	            return false;
	        }
	        for (int i = 0; i < targ; i++) {
	            if (hash1[i] != hash2[i]) return false;
	        }
	        return true;
	    }
	    
	}

	public static String hashContent( String content ) {
		MD5 md5 = new MD5();
		md5.Update(content);
		md5.Final();
		return md5.asHex();
	}
	
	/* my old implementation - works on server only
	  public static String hashContent( String content ) {
		  try{
			  MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
			  digest. update(content.getBytes());
			  int hash = digest.hashCode();
			  return Integer.toHexString(hash);
		  } catch(Exception e){ 
			  e.printStackTrace();
			  return null;
		  } 
	  }
	  */
}
